<!DOCTYPE html>
<html class="reftest-wait">
  <!-- Test: if button has a custom error, it should be affected by :invalid
             pseudo-class. -->
  <link rel='stylesheet' type='text/css' href='style.css'>
  <body onload="document.getElementById('b').setCustomValidity('foo'); document.documentElement.className='';">
    <button class='invalid' id='b'></button>
  </body>
</html>
